Gene Expression and Signal Transduction in Transformatio

转化中的基因表达和信号转导

• 批准号: 7337956
• 负责人: J F MUSHINSKI
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7337956
• 关键词: Gene; Expression; Signal; Transduction; Transformatio

The chief objective of our research is to understand the molecular and genetic mechanisms responsible for differentiation, cell growth, and neoplastic transformation. We study the oncogenes, tumor-suppressor genes and signal-transducing proteins in mouse and human experimental tumor systems, including BALB/c mouse plasmacytomas, B-cell lymphomas, and NIH 3T3 cells, among others. These are valuable experimental models, because they can be used to devise more specific therapy and preventive measures for human multiple myeloma, non-Hodgkin's lymphomas, and other human malignancies. BALB/c plasmacytomas, like human Burkitt lymphomas, are characterized by constitutive expression of the proto-oncogene, c-Myc. To determine which additional genetic alterations are required for complete transformation, we are using microarray hybridization studies of global gene expression to follow changes in gene expression during progression from pre-malignant to fully malignant plasma cell tumors. We are also using microarray hybridization studies to probe the molecular mechanisms at work in development of plasma cell tumors in mice and the mechanisms whereby certain transgenes and viral oncogenes accelerate this neoplastic process. Global gene expression studies are also underway to determine the physiological changes necessary for these tumors to adapt to growth in tissue culture. It is our hypothesis that such adaptive changes in gene expression that enable tumor cells to grow in the foreign environment of culture vessels might be analogous to those needed for human tumors to grow in alien environments following invasion or metastasis.In the study of signal transduction in differentiation and neoplastic transformation, we are investigating the isoform-specific features of the protein kinase C (PKC) family of serine/threonine kinases. We have been focusing on the delta and epsilon isoenzymes, which have opposing effects on cell proliferation. We have shown that most of the isoenzyme-specific determinants are located in the catalytic half (the carboxyl-terminal domain) of these PKCs by creating reciprocal chimeric cDNAs that encode molecules that are half PKC-delta and half PKC-epsilon. We are further dissecting the structure of the catalytic domain to determine which sub-domains determine PKC isoform- specific functions, focusing on the carboxy-terminal 50 amino acids, the "V5 domain." We are also studying the nature of PKC's involvement in apoptosis, in cytoskeleton-related changes in cell shape and motility, and in cooperation with the c-Myc proto-oncogene. We have shown that phorbol ester-activation of overexpressed PKC-delta disrupts the actin cytoskeleton in human and mouse lymphocytes, leading to the loss of membrane ruffling, a surface alteration needed for cell movement, and the loss of the typical elongated shape of these cells. We have demonstrated that this effect is due to PKC-mediated changes in phosphorylation of key tyrosine residues in the adaptor molecule, paxillin. Whereas the PKC-mediated effects on loss of tyrosine phosphorylation are indirect, we also have learned that PKC-delta can directly bind paxillin and phosphorylate a specific threonine, leading to homotypic aggregation.We have also shown that Myc and one of the PKC isoforms, PKC-gamma, can cooperate to transform NIH3T3 cells in vitro and in vivo, apparently not requiring intra-nuclear Myc. We are trying to understand the mechanism whereby this is accomplished.

我们研究的主要目的是了解负责分化，细胞生长和肿瘤转化的分子和遗传机制。我们研究了小鼠和人类实验性肿瘤系统中的肿瘤基因，肿瘤抑制基因和信号转推蛋白，包括BALB/C小鼠浆细胞瘤，B-细胞淋巴瘤和NIH 3T3细胞等。这些是有价值的实验模型，因为它们可用于为人类多发性骨髓瘤，非霍奇金淋巴瘤和其他人类恶性肿瘤制定更具体的疗法和预防措施。 BALB/C浆细胞瘤，例如人伯基特淋巴瘤，其特征在于原始癌基因c-myc的本构表达。为了确定完全转化需要哪些其他遗传改变，我们使用的是对全球基因表达的微阵列杂交研究遵循从恶性前到完全恶性血浆细胞肿瘤进展过程中基因表达的变化。我们还使用微阵列杂交研究来探测小鼠浆细胞肿瘤发育中起作用的分子机制以及某些转基因和病毒性致癌基因加速这种肿瘤过程的机制。还在进行全球基因表达研究，以确定这些肿瘤适应组织培养的生长所需的生理变化。 It is our hypothesis that such adaptive changes in gene expression that enable tumor cells to grow in the foreign environment of culture vessels might be analogous to those needed for human tumors to grow in alien environments following invasion or metastasis.In the study of signal transduction in differentiation and neoplastic transformation, we are investigating the isoform-specific features of the protein kinase C (PKC) family of serine/threonine kinases.我们一直专注于三角洲和埃普西隆同工酶，它们对细胞增殖有相反的影响。我们已经表明，大多数同工酶特异性决定因素位于这些PKC的催化半（羧基末端结构域）中，通过创建编码半pkc-delta和一半pkc-epsilon的相互嵌合cDNA。我们正在进一步剖析催化结构域的结构，以确定哪些子域确定PKC同工型 - 特异性功能，重点是羧基末端50氨基酸，即“ V5结构域”。我们还研究了PKC参与细胞凋亡的性质，细胞骨架相关的细胞形状和运动性变化以及与C-MYC原始癌中的合作。我们已经表明，过表达PKC-DELTA的佛波酯激活破坏了人和小鼠淋巴细胞中肌动蛋白的细胞骨架，导致膜皱纹的丧失，细胞运动所需的表面改变以及这些细胞典型的细胞形状的丧失。我们已经证明了这种作用是由于PKC介导的衔接子分子Paxillin中关键酪氨酸残基磷酸化的变化。 Whereas the PKC-mediated effects on loss of tyrosine phosphorylation are indirect, we also have learned that PKC-delta can directly bind paxillin and phosphorylate a specific threonine, leading to homotypic aggregation.We have also shown that Myc and one of the PKC isoforms, PKC-gamma, can cooperate to transform NIH3T3 cells in vitro and in vivo, apparently not需要核内myc。我们正在尝试了解实现这一目标的机制。